Circuit interrupter construction



Dec. 17, 1957 s. I. LINDELL 2,816,980

CIRCUIT INTERRUPTER CONSTRUCTION Filed March 9, 1955 5 Sheets-Sheet 1 IN V EN TOR.

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Dec; 17, 1957 s. l. LINDELL 2,816,980

CIRCUIT INTERRUPTER CONSTRUCTION filed March 9, 1955 5 Sheets-Sheet 2 INV ENTOR.

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CIRCUIT INTERRUP'I'ER CONSTRUCTION il-ed March 9, 1955 5 Sheets-Sheet 4 INVENTOR.

United States Patent CIRCUIT INTERRUPTER CONSTRUCTION Sigurd I. Lindell, Chicago, Ill., assignor to S 85 C Electric Company, Chicago, 11]., a corporation of Delaware Application March 9, 1955, Serial No. 493,083

27 Claims. (Cl. 200-114) This invention relates, generally, to circuit interrupters and it has particular relation to such devices for operation in conjunction with disconnecting fuses, switches and the like for opening them under load without drawing an external arc. This invention is an improvement over the inventions of Lindell Patent No. 2,671,142 and 2,671,145, both issued March 2, 1954, and Lindell application Serial No. 412,182 filed February 24, 1954.

Among the objects of this invention are: To provide for quickly and positively engaging a horn or stud projecting from a stationary contact of a disconnecting fuse or switch by manipulation of a load interrupter; to employ for this purpose a rockably mounted bow shaped contact member; to provide for similarly engaging the eye or pull ring of the movable fuse tube or switch blade after the horn or stud has been engaged to provide a shunt circuit therebetween and subsequently to operate the fuse tube or switch blade from closed to open position; to accomplish this engagement with the eye or pull ring by an arm on the load interrupter in combination with a cooperating keeper rockable about two axes at right angles to each other; to separate the contacts of the load interrupter as the result of withdrawing an insulating sleeve from an insulating housing and to latch automatically the sleeve and housing in separated relation; to utilize a spring biased latch movable with the sleeve for externally engaging the housing to hold them apart; to mount the housing and sleeve for manipulation on an externally extending arm which is flexibly mounted on the strut and to provide a rigid mechanical connection therebetween; to removably mount an arc extinguishing sleeve within the inner insulating sleeve of the interrupter and to provide a substantially fluid tight seal therebetween; and to interconnect the movable contact of the load interrupter and the insulating trailer by an insulator.

Other objects of this invention will, in part, be obvious and in part appear hereinafter.

This invention is disclosed in the embodiment thereof shown in the accompanying drawings and it comprises the features of construction, combination of elements and arrangement of parts that will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of this invention, reference can be had to the following detailed description, taken together with the accompanying drawings, in which:

Figure 1 is a perspective view of a circuit isolating device, such as a disconnecting fuse, showing how the auxiliary circuit interrupter of the present invention can be applied thereto, the particular circuit isolating device being that disclosed in Lindell application Serial No. 367,801, filed July 14, 1953, and assigned to the assignee of this application;

Figure 2 is an elevational view showing how the auxiliary circuit interrupter is mounted on a live line tool for relative movement in opposite directions with respect to ice its longitudinal axis in a plane parallel to the plane containing the same;

Figure 3 is a side elevational view showing how the auxiliary circuit interrupter can be held in fixed position with respect to the live line stick when it is desired to employ the latter solely for manipulating the disconnecting fuse or disconnecting switch blade;

Figure 4 is a side elevational view showing the first step employed in applying the auxiliary circuit interrupter to a circuit isolating device;

Figure 5 is a side elevational view showing the second step employed in applying the auxiliary circuit interrupter to a circuit isolating device, this view showing the auxiliary circuit interrupter positioned so as to provide a shunt circuit between the separable energized current carrying terminals or contacts of the circuit isolating device;

Figures 6 and 6A, taken together with the latter positioned below the former, show a longitudinal sectional view, at an enlarged scale, of the internal details of construction of the auxiliary circuit interrupter in which this invention is embodied;

Figure 7 is a top plan view of the upper portion of the auxiliary circuit interrupter shown in Figure 6, a portion of the screw plug being broken away in order to illustrate more clearly the internal details of construction;

Figure 8 is a horizontal sectional view taken generally along the line 88 of Figure 6;

Figure 9 is a view illustrating how the support member or strut is held in fixed relation with respect to the auxiliary circuit interrupter to permit the manipulation illustrated in Figure 3;

Figure 10 is a view, in front elevation, of a portion of the auxiliary circuit interrupter showing in detail the support member or strut which is mounted rigidly on the live line stick;

Figure 11 is a View, in side elevation, of the auxiliary circuit interrupter, certain portions being broken away in order to illustrate the internal details of construction, the parts being shown in the positions occupied thereby just prior to separation of the contacts for interrupting the circuit;

Figure 12 is a view, similar to Figure 11, except that the contacts are shown in the fully separated position and the housing is shown latched against movement with respect to the inner insulating sleeve; and

Figure 13 is a sectional view, at an enlarged scale, taken generally along the line 1313 of Figure 12.

Referring now particularly to Figure 1 of the drawings, it will be observed that the reference character 10 designates, generally, a circuit isolating device of the disconnecting fuse type. As pointed out hereinbefore, the details of construction of the circuit isolating device 10 are set forth in Lindell application Serial No. 367,801. Accordingly, only a general description of this device will be set forth here. While particular reference is made to a disconnecting fuse device, it will be understood that the present invention can be employed where the fuse tube of the disconnecting fuse is replaced by a metallic conducting tube or it can be used in conjunction with a disconnecting switch that is modified suitably for adaptation to be used in conjunction with the auxiliary circuit interrupter mounted on a live line stick as described hereinafter.

The circuit isolating device or disconnecting fuse 10 includes an insulator 11 which is arranged to be stationarily mounted on a cross arm or the like and has a lower terminal contact member 12 carrying a connector 13 for connection to a line terminal. Pivoted at 14 on the lower terminal contact member 12 is a lower current carrying member 15 that is positioned at the lower end of a fuse tube 16. At its upper end the fuse tube 16 has an upper current carrying member 17 which is positioned O in contact engagement with a normally energized contact member 18 carried by the upper end of the insulator 11. In order to remove the upper current carrying member 17 from contact engagement with the terminal contact member 1.3, the former is provided with an eye or pull ring 19 of conducting material for receiving the prong of a live line tool. In accordance with conventional practice, the fuse tube 16 is manipulated by inserting the prong of the live line tool in the eye or pull ring 19 for swinging the upper current carrying member 17 into or out of contact engagement with the terminal contact member 18.

For purposes more fully disclosed in Lindell applica tion Serial No. 367,801, the terminal contact member 18 includes an L-shaped reinforcing bar 2% having a downwardly extending arm 21 which carries a guide 22. The guide 22 is employed, in part, for guiding the upper current carrying member into proper contact engagement with the terminal contact member 18. The guide 22 includes forwardly extending arms 23 at the outer ends of which are transversely extending horns or studs Provision is made for connecting the energized line conductor to the terminal contact member 18 through a terminal pad 25. It will be understood that the upper portion of the terminal pad 25 (not shown) carries a connector or the like device to facilitate connection of the energized line conductor thereto.

It is often necessary to open the circuit isolating device or disconnecting fuse 10 while it is carrying load current. When such operation is performed, an arc is drawn between the upper current carrying member 17 and the terminal contact member 13 which is likely to damage the parts which are contacted by the arc and also, where other circuits are involved, is likely to fault one or more circuits in the event that the arc is drawn and should jump to another circuit or the ground. Also there is the likelihood of injury to the operator. In accordance with the present invention, provision is made for safely and expeditiously opening the circuit isolating device 16 while it is carrying line current. It is for this purpose that the auxiliary circuit interrupter, shown generally at 27, is

employed.

It will be observed that the auxiliary circuit interrupter 27 is provided near its upper end with an eye member or pull ring that is shown, generally, at 2-8. The details of construction are shown more clearly in Figures 6 and 7 of the drawings. The eye member or pull ring 28 includes a bow shaped contact member 2% which has oppositely extending trunnions 30 that are rockably mounted by parallel end portions 31 of a pair of arm 32 that are formed integrally with and extend generally radially from a pull ring cap 33 which forms a part of a stationary contact assembly for the auxiliary circuit interrupter 27 that is shown, generally, at Coil springs 35' around the trunnions 3t? urge the bow shaped contact member 29 outwardly from the broken line position shown in Figure 6 to the full line position. The outward movement is limited by the lower ends 36 of the contact member 29 engaging shoulders 37 at the outer ends of the arms 32. It will be understood that the bow shaped contact member 29, as shown in Figure l, is positioned over one of the horns or studs 24 for connection to the normally energized terminal contact member of the circuit isolating device it). In addition, this connection serves as an anchor for resisting an endwise pull applied to the auxiliary circuit interrupter 27, in a manner to be described, not only for operating the fuse tube 16 to the open position but also for subsequently operating the auxiliary circuit interrupter 2,7 to interrupt the flow of load curernt therethrough.

Connection to the upper current carrying member 17 is provided by contact means it) in the form of a pin or prong that is carried by a support member All in the form of a strut, preferably formed of aluminum, on which the auxiliary circuit interrupter 27 is flexibly mounted by a universal joint that is indicated, generally, at in Figures 2 to 6 of the drawings. The support member or strut 41 has an integral extension 4-3 provided with a claw bracket 44 that can be secured by a clamp screw 45 to a similar claw bracket 4-6 that is formed integrally with a fitting 47 arranged to be carried by one end of a live line stick a portion of which is shown at 4-8 in Figure 1.

In order to insure that the pin or prong 4t) remains in engagement with the eye or pull ring 19 which constitutes an integral extension of the upper current carrying member 17, rotary keeper is employed which is rockably mounted at 59, as shown more clearly in Figures 3 to 6 of the drawings, to swing inwardly in order to permit entry of the pin or prong 46 into the eye or pull ring 1%. Figure 6 shows how the keeper can swing inwardly from the full line position to the position shown by the broken lines. Also, as there shown, the keeper 49 is carried by a pivot shaft 5:. that is arranged to rock about its longitudinal axis 512 so that the keeper 49 can be swung to either of the alternate positions shown by broken lines in Figure 2. it will be apparent now that the keeper 4-9 is rockable about two axes 5d and 52 generally at right angles to each other.

The pivot shaft 51, Figure 6, is rockably mounted in a hollow boss 53 that is formed inte rally with the support member or strut 41. At the end opposite the end where the keeper 49 is rockably mounted there is a transverse slot 54 which receives ends of a coil spring 56 that is wrapped around the shaft 51. These ends 55 of the spring 56 bear against shoulders 57 of the support member or strut 41 and thus function to bias the pivot shaft 51 back to the central position as shown in Figure 2. In order to bias the keeper 4-9 to the full line position shown in Figure 6, a plunger or follower 58 is slidably mounted within a bore 59 in the shaft 51 and it is urged outwardly by a coil compression spring 60. The outward movement of the keeper 49 under the influence of the spring 60 is limited by the engagement of the lower inclined end 61 of the keeper 4-9 with a shoulder 62 correspondingly inclined and located at the outer end of the pivot shaft 51. Snap rings 63 serve to position the pivot shaft 51 in the boss 53 and a snap ring 64 at the inner end with its ends secured together by a staple holds the ends 55 of the spring 56 in place in the transverse slot 54.

Since the pin or prong 10 may shift from one side to the other of the eye or pull ring 19 and cause arcing therebetween, contact is maintained by a V-shaped. spring contact shown generally at 65 in Figure 6. One arm 65a is secured to the upper end of the support member or strut 41 while the other arm 65b swings along an arcuate under surface 66 of the pin or prong 4%. A pin 65c extending transversely of the nadir of the spring contact 65 into the support member or strut 31 holds the former in place on the latter. As long as the eye or pull ring 119 lies underneath the pin or prong it) it will be in contact engagement with the arm 65b of the spring contact 65 and thus maintained electrically connected to the support member or strut 41.

As shown in Figure 6 the auxiliary circuit interrupter 27 includes a tubular insulating housing 67 that is formed preferably of a phenolic condensation product and it carries the stationary contact assembly 34 at its upper end. A screw plug 68 is threaded into the pull ring cap 33 and a rigid conductor rod 69 depends therefrom. Clamp nuts 70 hold the rod 69 in fixed relation with respect to the screw plug 68.

At its lower end the rigid conductor rod 69 carries a cam terminal 71 which is provided with a latch engaging shoulder 72 the purpose of which will be set forth presently. The cam terminal '71 is connected by a flexible conductor 73 and a coil spring 74 to a movable first arcing contact 75 which is provided with an annular contact insert 76 of arc resisting material. When the bow shaped contact member 29 engages the horn or stud 24 of the normally energized terminal contact member 18, the circ'uit is extended through the stationary contact assembly 34, rigid conductor rod 69, and flexible conductor 73 to the movable first arcing contact 75.

When the circuit is interrupted under load an arc is drawn from the movable arcing contact 75. In order to extinguish the are quickly a trailer 77 is moved conjointly with the arcing contact 75. The trailer 77 is formed of a material which, when subjected to the heat of the arc, will evolve an arc extinguishing medium. A preferred material for the trailer 77 is methylmethacrylate resin. Preferably the arcing contact 75 is connected to the trailer 77 by a trailer stud 78 that is formed of insulating material which is capable of withstanding the shock incident to rapid movement of the arcing contact 75. It has been found that nylon is satisfactory for this purpose and that it has the desired mechanical characteristics. As shown at the lower end of Figure 6 the trailer stud 78 is connected to the arcing contact 75 by a trailer stud pin 79 which extends transversely through both and provides a limited degree of flexibility for the connection therebetween. As shown more clearly in Figure 6A the trailer stud 70 extends through a longitudinal bore 80 in the trailer 77. At its lower end the trailer stud 78 has a head 81 which interfits with an enlarged bore 82 in the body of the trailer 77. An 0 ring 83, preferably formed of neoprene, is located in an annular groove 84 around the head 81 and serves to seal off the space between the bore 82 and the outer surface of the head 81.

As shown in Figure 6, the arcing contact 75 is threaded into the lower end of a tubular metallic sleeve 87 that is formed preferably of aluminum. At its upper end the sleeve 87 is arranged to cooperate with a trigger 88 that is pivoted at 89 between arms 90, Figure 7, which extend upwardly from a trigger frame stop 91. A spring 92 having coils on opposite sides of the trigger 88 and located around the pivot 89 functions to bias the trigger 88 to the position shown in Figure 6. The outward movement of the trigger 88 under the biasing action of the spring 92 is limited by a pin 85 which extends transversely between the arms 90 through a relatively large diameter opening 86 in the trigger 88. At its upper end the metallic sleeve 87 carries a stainless steel tube end insert 93 which is arranged to be engaged by the lower end of the trigger 88 when it is moved downwardly as will be described presently.

The trigger frame stop 91 is secured by screws 94 to an inner sleeve end insert 95 which is secured to the upper end of an inner insulating sleeve 96 formed preferably of a phenolic condensation product.

As shown more clearly in Figure 13 of the drawings longitudinally extending slots 97 are provided on opposite sides of the inner insulating sleeve 96, which is telescoped within the tubular insulating housing 67, and cooperating therewith are tongues or pins 98 which are carried by a ring 99 that is mounted on the insulating housing 67 as shown. The purpose of the cooperating slots 97 and tongues or pins 98 is to insure that the inner insulating sleeve 96 moves translatorily only with respect to the insulating housing 67 and that there is no relative rotary movement therebetween. The tongues or pins 98 also serve as stops for engaging shoulders 100 located at the bases of fingers 101, formed integrally with the trigger frame stop 91, to limit the extent that the inner insulating sleeve 96 can be withdrawn from the tubular insulating housing 67. When the inner insulating sleeve 96 is moved into the tubular insulating housing 67, such movement is limited by the engagement of the fingers 101 with the under side of the screw plug 68 as shown at the upper end of Figure 6.

It will be pointed out hereinafter that the tubular metallic sleeve 87 moves upwardly relative to the inner insulating sleeve 96 when the latter has been moved out of the tubular insulating housing 67 as shown in Figure 11 of the drawings. The upward movement of the metallic sleeve 87 is limited by a stop ring 102 which is formed integrally therewith intermediate its ends. This stop ring 102 is arranged to engage the under side of a contact tube stop ring 103, the contact tube referred to being the tubular metallic sleeve 87. As shown in Figure 6 the ring 103 is carried by and is located in the underside of the trigger frame stop 91. It is formed preferably of insulating material, such as nylon, which has the desired mechanical properties for cushioning the upward movement of the sleeve 87 under the influence of the coil tension spring 74.

When the arcing contact 75 is moved upwardly under the influence of the spring 74, it and the trailer 77 are drawn into a liner 106 that also is formed of a material which evolves an arc extinguishing medium when subjected to the heat of the arc. Preferably methylmethacrylate resin is employed for this purpose. Since the liner 106 may have to be removed as the result of erosion due to repeated operation of the auxiliary circuit interrupter 27, provision is made for facilitating this operatien. For the reasons outlined in Lindell application Serial No. 412,182, it is desirable that the axial position of the liner 106 be maintained. For this purpose a pin 107 extends radially therefrom as shown in the lower left hand portion of Figure 6. The pin 107 is arranged to interfit with a slot 108 that extends longitudinally along the inner wall of the inner insulating sleeve 96. This locates the liner 106 in the proper axial position.

With a view to scaling off the space between the outer surface of the liner 106 and the inner surface of the juxtaposed portion of the inner insulating sleeve 96, the latter is provided with annular grooves 109 near the ends of the liner 106 and 0 rings 110 of neoprene are inserted therein. A shallow annular groove 111 is provided around the lower end of the liner 1'86 for receiving the associated 0 ring 110. This construction is such that, while the liner 106 can be removed by a downward endwise pressure applied to its upper end, an effective seal is provided over the outer surface of the liner 106 which prevents the escape thereover of the products of the arc and reduces the likelihood of arcing over this surface which otherwise might occur if it were not sealed off as described. In the event that gas pressure should build up between the liner 106 and the sleeve 96, such pressure will act on the 0 rings 110 to tighten the seal therebetween.

As illustrated in Figures 6 and 6A, a movable contact assembly, shown generally at 112, cooperates with the movable first arcing contact 75. It is pointed out hereinafter how the contact assembly 112 and contact 75 move as a unit during a part of the cycle of operation of the auxiliary circuit interrupter 27. The contact assembly 112 includes a metallic contact sleeve 113 which is secured to the inside of the lower end of the inner insulating sleeve 96 and is movable conjointly therewith. The contact sleeve 113 has a depending extension 114 which defines a chamber 115 into which the products of the are are blown on the separation of the arcing contact 75 from the contact assembly 112 in a manner to be described. Radial vents 116 serve to place the chamber 115 directly in communication with the atmosphere when the inner sleeve 96 is withdrawn from the insulating housing 67 as shown in Figures 11 and 12 of the drawings. Within the metallic contact sleeve 113 is an inner contact sleeve 117 which is secured to the former by a contact locating screw 118. Extending upwardly from the inner contact sleeve 117 are flexible contact fingers 119 which are provided with contact tips 120 that are arranged to engage the outer surface of the arcing contact 75 as shown at the lower portion of Figure 6. A contact retaining ring 122 limits the radial inward movement of the contact tips 120 under the influence of :a biasing spring (not shown). Since the contact construction is illustrated and described in detail in Lindell application Serial No. 412,182, no further description '7 thereof will be set forth herein other than to point out that the longitudinal slots provided between the contact fingers 119 serve as passageways through which the are products can flow into the chamber 115 when the circuit interrupter 27 is called upon to interrupt the circuit under load.

Threaded into the lower end of the extension 1141 s a hollow light transmitting plug 123 which is provided with radial vents 124 also to permit the escape of the are products when the device is operated to the position shown in Figures 11 and 12. A screen formed of wire mesh and indicated at is located within the chamber 115 and overlies the vents lid and its purpose is to cool the are products before they are discharged and to prevent the expulsion of solid particles from the chamber 115.

it has been pointed out hereinbefore that the auxiliary circuit interrupter 27 is mounted by the universal joint 42 on the support member or strut 4-1. This is accomplished through the agency of a conducting arm 12% that is formed integrally with the metallic contact sleeve 113 and extends radially upwardly therefrom as shown more clearly in Figures 3 to 6 and 6A of the drawings. The conducting not only serves to support mechanically the circuit interrupter 1.7 but also it functions to complete the circuit through the device from the contact fingers M9 and the metallic contact sleeve 113 to the eye or pull ring 19 and thereby to the upper current carrying member 1'7 of the fuse tube 16. The arm i2 3 extends through a longitudinal slot 129 at the lower end of the tubular insulating housing 67. The upper end portion 13% of the arm is generally parallel to the longitudinal axis of the circuit interrupter 27 and has a generally H-shaped cross section. At the upper end of the parallel portion 33ft there is an upwardly opening slot 13% through which a rod or shaft 131 extends transversely to form a part of the universal joint 42 referred to previously. The rod or shaft 131 extends between arms 132 which extend forwardly from and are formed integrally with the support member or strut ll. By means of the shaft 131 the auxiliary circuit interrupter 2'7 is permitted to rock about an axis perpendicular to the plane of Figure 6 toward and away from the support member or strut ll. A spring 133 cooperates with the auxiliary circuit interrupter 2'7 and the support member or strut ll to bias the latter toward the former or to the position illustrated in Figure 6.

The rod or shaft 131 extends transversely through a rod or shaft l3=i which, in turn, extends through arms 135 and 336 which define the slot 139. The shaft 134, extending at right angles to the rod or shaft 13E, supports the auxiliary circuit interrupter 27 for movement in a plane at right angles to the plane of movement about the shaft Thus the universal joint 42 is formed, in part, by the rod or shaft 131 and, in part, by the rod or shaft 13 3-.

In order to center the auxiliary circuit interrupter 27 with respect to the support member or strut 41, the ends 137 of a coil spring 138, wound around the rod or shaft 134, extend in opposite directions through a slot 139 in the outer end and bear against an arcuate flange 140 that extends from the portion 13% that projects upwardly from the conducting arm Snap rings 141, located on the outer sides of the arms 1% and 136 and beyond the ends 137 serve to hold the rod or shaft 134 in position and to keep these ends 137 within the slot 139. The snap ring 141 at the right hand end of the shaft 134 is provided with a staple M2 to hold its ends inseparable.

As polnted out hereinbefore it is desirable to hold the support member or strut 4i rigid with respect to the auxiliary circuit interrupter 27 so that the former can be employed, as illustrated in Figure 3, for manipulating the fuse 16 independently of the auxiliary circuit interrupter 27. For this purpose this construction shown in Figure 9 can be employed. As there illustrated a manually operable stop 1143 is rock-ably mounted about the axis 144 of a handle 145 on the support member or strut 41 below the universal joint 4 In the unoperated position of the stop 143, shown in Figure 6, a shoulder 14-6 thereof engages the underside of the arcuate flange 14-0 at its outer end and limits the swing of the support member or strut 41 as biased toward the auxiliary circuit interrupter 27 by the spring 133. Now when the stop 143 is rotated about the axis to the position shown in Figure 9, cl ii 147 engages the under side of the arcuate v i 11"; and effectively prevents the spring 133 from moving the support member or strut ll toward the auxiliary circ it interrupter 27. In this position the stop 143 holds the support member or strut ll rigidly with respect to the auxiliary circuit interrupter 27 and thus permits the ope ate-r to manipulate the fuse tube 16 or the blade of .connectlng switch by the operation of the live line stick it; just as would be possible if the auxiliary circuit interru ter 27 were not present.

After the circuit has been opened by the separation of the arcing contact 75 from the contact assembly 112, it is desirable to latch the inner insulating sleeve 96 in the extended position with respect to the insulating housing n7. for this purpose a latch 148, Figures 6 and 12, is employed. The latch formed preferably of insulating material which is capable of withstanding mechanical shock. it has been found that nylon is a suitable material for this purpose. The latch 143 is rockably mounted on a pin 3.4-9 which extends through the upper end of the arm as shown in Figure 6. it is biased in a counterclockwise direction by a spring 151} which surrounds the pin 149 on opposite sides of the portion of the arm that extends upwardly between the downwardly projecting arms 151 of the latch The upper end 152 of the latch is arcuately shaped in order to conform generally to the curvature of the outer surface of the tubular insulating housing 67.

In operation, when it is desired to operate a circuit isolating device, such as the device ltl previously described, 0 the open circu' position when it is carrying current, ne auxiliary circuit interrupter 27 described herein can be employed. For this purpose the stop 143 is positioned as shown in Figure 6 where it is inoperative to prevent movement of the circuit interrupter 27 about the axis of the rod or shaft 13L it is assumed, further, that the arcing contact is in engagement with the contact tips 12% of the contact fingers 119 so that the circuit is completed through the device. The position of the parts under these conditions is as illustrated in Figures 6 and 6A of the drawings.

The lineman grasps the live line stick 48 and manipulates the bow shaped contact member 29 so that it engages one or the other of the horns or studs 24 of the gods 22. This causes the metallic parts of the auxiliary circuit interrupter 27 to be energized at the potential of the terminal contact member In addition it serves as an anchor which holds the contact assembly 34 stationary while permitting the withdrawal of the inner insulating sleeve 96 and parts associated therewith. The manipulation thus far described is illustrated in Figure 4 of the drawings.

Next the live line stick is swung to cause the pin or prong iti to enter the eye or pull ring 19 as shown in gure 5 and deflect the arm 65b of the spring contact 6:). In doing this the keeper is swung inwardly as shown by broken lines in order to permit the eye or pull ring 19 to receive the pin or prong Eli.

When the pin or prong lit engages the eye or pull ring 19, the am iary circuit interrupter 27 is placed in shunt circuit relation between the terminal Contact member ill and the upper current carrying member l"! on the fuse tube id. The spring contact 65 insures that the circuit is maintained without arcing to the eye or pull ring It is then possible to separate the upper current carrying mem- 17 from the terminal Contact member 18 without arcing since the flow of current is transferred to the auxiliary circuit interrupter 27.

Thereafter the operator pulls downwardly on the live line stick 48 to separate further the upper current carrying member 17 from the terminal contact member 18. This movement is permitted by the universal joint 42. When the operator manipulates the live line stick 48, the pin or prong 4i cannot escape from the eye or pull ring 19 because of the keeper 49. If the keeper 49 is not used, there is the possibility that the pin or prong 40 might slip out of the eye or pull ring 19 and permit the fuse tube 16 to drop before the auxiliary circuit interrupter 27 could operate to open the circuit. In that event, an arc would be drawn between the eye or pull ring 19 and the pin or prong 40 which should be avoided and is avoided when the keeper 49 is used.

As the live line stick 48 is moved downwardly, the inner insulating sleeve 96 is withdrawn from the tubular insulating housing 67. This is shown in Figure 11 of the drawings. Shortly after this downward movement is initiated, the trigger 88 engages the tube end insert 93 and causes the metallic sleeve or contact tube 87 to move downwardly together with the arcing contact 75 and the contact assembly 112. This is accompanied by a stressing of the coil tension spring 74. This movement continues until the lower rounded end of the trigger 88 engages the shoulder '72 of the cam terminal 71, the relationship being illustrated in Figure 11. When this occurs, the metallic sleeve 87 no longer is restrained and it and the arcing contact 75 are moved upwardly as the spring 74 collapses. The arcing contact 75 moves out of engagement with the contact tips 120 at the upper ends of the flexible contact fingers 119 to interrupt the circuit. This separation is accompanied by the drawing of an arc therebetween. As described previously, this arc is drawn into the liner 106 where it is confined by the trailer 77 and is extinguished by the evolution of arc extinguishing material from the surfaces contacted by the arc.

The downward movement of the inner insulating sleeve 96 continues until the tongues or pins 98 engage the shoulders 100, Figure 13. At about this same time the upward movement of the metallic sleeve 87 and the arcing contact 75 is arrested by the engagement of the stop ring 102 with the stop 103 of insulating material carried by the trigger frame stop 91, also as shown in Figure 13.

The relationship of the inner insulating sleeve 96 to the tubular insulating housing 67 in the extended position is shown in Figure 12 where it will be apparent that the latch 148 has been urged by the spring 150 to a position underneath the lower end of the insulating housing 67. This effectively prevents the return of the inner insulating sleeve 96 into the insulating housing 67. Since the latch 148 holds the insulating sleeve 96 in the extended position, there is no likelihood of the fuse tube 16 being swung back toward or to closed position Where restriking of the arc might occur while the live line stick 48 is being manipulated to disengage the bow shaped contact member from the horn or stud 24. This is important from the standpoint of safety.

If desired, instead of the latch 148 being arranged to provide a positive stop against return of the inner insulating sleeve 96 into the insulating housing 67 on an upward thrust applied to the live line stick 48, the upper end of the latch 148 can be shaped so as to provide a friction lock which can be overcome by the application of an increased upward thrust to the live line stick 48.

It is desirable now to disengage the pin or prong 40 from the eye or pull ring 19. This is accomplished by turning the live line stick 48 about its longitudinal axis in one direction or the other so that the pin or prong 40 is rotated out of the eye or pull ring 19. This is permitted since the keeper 49 can rotate about the axis 52 of the pivot shaft 51, as shown in Figures 2 and of the drawings. When the pin or prong 40 is removed from the eye 10, or pull ring 19, the fuse 16 then swings downwardly under the influence of gravity to the full open position. Thereafter the bow shaped contact member 29 can be lifted upwardly from the horn or stud 24 whereupon the auxiliary circuit interrupter 27 is deenergized.

Subsequently the lineman can manually release the latch 148 and return the insulating sleeve 96 into the tubular insulating housing 67 at which time the parts reassume the positions shown in Figures 6 and 6A of the drawings.

The bow shaped contact member 29 can be disengaged from the horn or stud 24 after the circuit is opened by the auxiliary circuit interrupter 27 by moving the latter upwardly and subsequently the pin or prong 40 can be removed from the eye or pull ring 19. When this sequence of steps is employed, the fuse tube 16 can be brought down to open position under the control of the operator rather than being allowed to drop to open position under the influence of gravity. Then the pin or prong 40 is removed from the eye or pull ring 19 in the manner described.

Since certain further changes can be made in the foregoing construction and different embodiments of the invention can be made without departing from the spirit and scope thereof, it is intended that all matter shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact memher and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact means for electrical connection to said contact member, said contact making means including a bow shaped rockably mounted member adapted to overlie a part of said terminal contact member, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said current carrying member, a pair of separable contacts in said sleeve connected respectively to said conducting members, and means for separating said contacts to open the circuit therethrough.

2. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact means for electrical connection to said contact member, said contact making means including a pair of arms having a bow shaped member rockably mounted at their outer ends for overlying a part of said terminal contact member with spring means biasing said bow shaped member to a given position relative to said arms, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said current carrying member, a pair of separable contacts in said sleeve connected respec-- tively to said conducting members, and means for separating said contacts to open the circuit therethrough.

3. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said contact member, an inner insulating sleeve relatively slidably mounted Within said housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said current carrying member, the last named contact means including a prong for entering a ring member on said current carry ing member and a rockably mounted keeper cooperating with said prong to prevent disengagement thereof with said ring, a pair of separable contacts in said sleeve connected respectively to said conducting members, and means for separating said contacts to open the circuit therethrough.

4. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said contact memher, an inner insulating sleeve relatively slidably mounted Within said housing having a conducting member secured thereto carrying externally extending contact means for electrical connection to said current carrying member; the last named contact means including a prong for entering a ring member on said current carrying member, a keeper rockably mounted about two axes at right angles to each other, and resilient means individual to each axis and biasing said keeper to cooperate with said prong to prevent disengagement thereof from said ring and permit entrance thereto and exit therefrom; a pair of separable contacts in said sleeve connected respectively to said conducting members, and means for separating said contacts to open the circuit therethrough.

5. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said contact member, said contact making means including a bow shaped rockably mounted member adapted to overlie a part of said terminal contact member, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto carrying externally a ending contact making means for electrical connection to said current carrying member, the last named contact means including a prong for entering a ring member on said current carrying member and a rockably mounted keeper cooperating with said prong to prevent disengagement thereof with said ring, a pair of separable contacts in said sleeve connected respectively to said conducting members, and means for separating said contacts to open the circuit therethrough,

6, A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact memher and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact means for electrical connection to said contact member, said contact making means including a pair of arms having a bow shaped member rockably mounted at their outer ends for overlying a part of said terminal contact member with spring means biasing said bow shaped member to a given position relative to said arms, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said current carrying member; the last named contact means including a prong for entering a ring member on said current carrying member, a keeper rockably mounted about two axes at right angles to each other, and resilient means individual to each axis and biasing said keeper to cooperate with said prong to prevent disengagement thereof from said ring and permit entrance thereto and exit therefrom; a pair of separable contacts in said sleeve connected respectively to said conductmg members, and means for separating said contacts to open the circuit therethrough.

7. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said contact member, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said current carrying member, a pair of separable contacts in said sleeve connected respectively to said conducting members, a sprmg connected to one of said contacts and acting to bias the latter for movement away from the other contact with a force depending upon the extent of relative move ment apart of said housing and sleeve, means for releasing said one contact for movement under the influence of said spring when said sleeve has been moved relatively away from said housing to a given position, and latch means cooperating with said sleeve and said housing for holding them in separated position after said contacts have separated.

8. The invention as set forth in claim 7 wherein the latch means is friction latch means and is releasable on application of a given endwise thrust on the sleeve.

9. A circuit interrupter for opening a high vol cu1t 1solating device such as a disconnecting fuse, \LbvC li" necting switch or the like, normally carrying lino current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact makmg means for electrical connection to said contact member, said contact making means including a bow shaped rockably mounted member adapted to overlie a part of said terminal contact member, an inner insulating slee e relatively slidably mounted within said housing hav'ig conducting member secured thereto carrying externally extending contact making means for electrical connez: to said current carrying member, the last named contact means including a prong for entering a ring member on said current carrying member and a rockably mounted keeper cooperating with said prong to prevent disengagement thereof with said ring, a pair of separable cont. cts in said sleeve connected respectively to said conducting members, a spring connected to one of said contacts and acting to bias the latter for movement away from the other contact with a force depending upon the extent of relative movement apart of said housing and sleeve, 1115:?13 for releasing said one contact for movement under the l fluence of said spring when said sleeve has been moved relatively away from said housing to a given position, and latch means cooperating with said sleeve and said housing for holding them in separated position after said contacts have separated.

10. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said contact member, said contact making means including a pair of arms having a bow shaped member rockably mounted at their outer ends for overlying a part of said terminal contact member with spring means biasing said how shaped membertto a given position relative to said arms, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said current carrying member; the last named contact means including a prong for entering a ring member on said current carrying member, a keeper rockably mounted about two axes at right angles to each other, and resilient means individual to each axis and biasing said keeper to cooperate with said prong to prevent disengagement thereof from said ring and permit entrance thereto and exit therefrom; a pair of separable contacts in said sleeve connected respectively to said conducting members, a spring connected to one of said contacts and acting to bias the latter for movement away from the other contact with a force depending upon the extent of relative movement apart of said housing and sleeve, means for releasing said one contact for movement under the influence of said spring when said sleeve has been moved relatively away from said housing to a given position, and latch means cooperating with said sleeve and said housing for holding them in separated position after said contacts have separated.

11. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said contact member, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said current carrying member, a pair of conjointly movable separable contacts in said sleeve connected respectively to said conducting members, movement of said sleeve relatively away from said housing effecting conjoint movement of said separable contacts away from said conducting member on said housing, spring means operatively interconnecting said housing and one of said contacts and acting to bias the latter for movement away from the other contact with a force depending upon the extent of relative movement apart of said housing and sleeve, means for releasing said one contact for movement under the influence of said spring when said sleeve has been moved relatively away from said housing to a given position, and a latch carried by said contact making means on said sleeve and cooperating with said housing to hold the same in separated position.

12. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said contact member, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto with an externally extending rigid conducting arm carrying contact making means for electrical connection to said current carrying member, a pair of conjointly movable separable contacts in said sleeve connected respectively to said conducting members, movement of said sleeve relatively away from said housing effecting conjoint movement of said separable contacts away from said conducting member on said housing, spring means operatively interconnecting said housing and one of said contacts and acting to bias the latter for movement away from the other contact with a force depending upon the extent of relative movement apart of said housing and sleeve, means for releasing said one contact for movement under the influence of said spring When said sleeve has been moved relatively away from said housing to a given position, and a latch carried by said arm and biased into the path of said housing to hold the same and said sleeve in separated position after said contacts have separated 13. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said contact member, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto with an externally extending conducting arm carrying contact making means for electrical connection to said current carrying member including a strut flexibly mounted on said arm, a pair of separable contacts in said sleeve connected respectively to said conducting members, spring means connected to one of said contacts and acting to bias it for movement away from the other contact with a force depending upon the extent of relative movement apart of said housing and sleeve, means for releasing said one contact for movement under the influence of said spring when said sleeve has been moved relatively away from said housing to a given position, and manually operable stop means cooperable with said arm and strut to provide a rigid mechanical connection therebetween.

14. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said contact member, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto with an externally extending conducting arm carrying contact making means for electrical connection to said current carrying member including a strut flexibly mounted on said arm, a pair of separable contacts in said sleeve connected respectively to said conducting members, spring means connected to one of said contacts and acting to bias it for movement away from the other contact with a force depending upon the extent of relative movement apart of said housing and sleeve, means for releasing said one contact for movement under the influence of said spring when said sleeve has been moved relatively away from said housing to a given position, and a stop member rockably mounted on said strut and movable into locking engagement with said arm to provide a rigid mechanical connection therebetween.

15, circuit interrupter for opening a high voltage circuit solating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination,

a tubular insulating housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said contact member, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto with an externally extending conducting arm carrying contact making means for electrical connection to said current carrying member including a strut flexibly mounted on said arm, a pair of separable contacts in said sleeve connected respectively to said conducting members, spring means connected to one or" said contacts and actin to bias it for movement away from tlie other contact with a force depending upon the extent of relative movement apart of said housing and sieeve, means for releasing said one contact for movement under the influence of said spring when said sleeve has been moved relatively away from said housing to a given position, manually operable stop means cooperable with said arm and strut to provide a rigid mechanical connection therebetween, and a latch carried by said arm and biased into the path of said housing to hold the same and said sleeve in separated position.

16. A circuit interrupter for opening a hi h voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member mo /ab e into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said contact member, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto with an externally extending conducting arm carrying contact making means for electrical connection to said current carrying member including a strut flexibly mounted on said arm, a pair of separabl contacts in said sleeve connected respectively to said conducting members, spring means connected to one of said contacts and acting to bias it for movement away from the other contact with a force dependin' upon the extent of relative movement apart of said housing and sleeve, means for releasing said one contact for movement under the influence of said spring when said sleeve has been moved relatively away from said housing to a given position, a stop member rockably mounted on said strut and movable into locking engagement with said arm to provide a rigid mechanical connection therebetween, and a latch carried by said arm and biased into the path of said housing to hold the same and said sleeve in separated position.

17. A live line handling tool for mounting on a live line stick comprising, in combin tion, a strut adapted to be rigidly mounted on said stick, a prong carried by said strut and extending transversely thereof for entering a ring member of an energized electrical device to shift it from one position to another, and a keeper rockably mounted on said strut in spaced relation to said prong and cooperating therewith to prevent its disengagement from said ring, said keeper being yieldable in a direction transver e to its of rotation to permit disconnection of said prong from said ring member by twisting said strut about the longitudinal axis of said stick.

18. A live line handling tool for mounting on a live line stick comprising, in combination, a strut adapted to be rigidly mounted on said stick, a prong carried by said strut and extending transversely thereof for entering a ring member of an energized electrical device to shift it from one position to another, a keeper rocksbly mounted on said strut about two axes at right angles to each other, and resilient means individual to each axis and biasing said keeper to cooperate with said prong to prevent disengagement thereof from said ring and permit entrance thereto and exit therefrom.

19. A live line handling tool for mounting on a live line stick comprising, in combination, a strut adapted to be rigidly mounted on said stick, a prong carried by said strut and extending transversely thereof for entering a ring member of an energized electrical device to shift it from one position to another, a keeper rockably mounted on said strut in spaced relation to said prong about an axis parallel thereto and also about an axis in a plane at right angles thereto and extending into juxtaposition to said prong, resilient means biasing said keeper about each axis to cooperate with said prong to prevent disengagement thereof from said ring and permit entrance thereto and exit therefrom, and stop means limiting the movement of said prong away from said strut.

20. A circuit interrupter comprising, in combination, an insulating sleeve having an inwardly opening longitudinal slot at one end, a liner removably telescoped within said one end of said sleeve having at one end a radially outwardly extending pin for entering said slot to hold said liner and sleeve in predetermined relation and a sore from which an arc extinguishing medium is evolved due to the heat of an arc, cylindrical contact means in endwise spaced relation to one end of said bore and movable into and substantially filling the same, a trailer of insulating material capable of evolving an are extinguishing medium when subjected to the heat of an arc and movable with said contact means into said bore, and a plurality of contact fingers engaging the periphery of said contact means at said one end of said bore.

21. A circuit interrupter comprising, in combination, an insulating sleeve having an inwardly opening longitudinal slot at one end and a pair of inwardly opening spaced annular grooves intermediate its ends, a liner removably telescoped within said one end of said sleeve and overlying said annular grooves and having at one end a radially outwardly extending pin for entering said slot to hold said liner and sleeve in predetermined relation and a bore from which an arc extinguishing medium is evolved due to the heat of an are, resilient 0 rings having substantially more than half their diameters within said grooves and engaging the juxtaposed outer surface portions of said liner to provide fluid tight sealing engagement therewith, cylindrical contact means in endwise spaced relation to one end of said bore and movable into and substantially fillin the same, a hollow trailer of insulating material capable of evolving an arc extinguishing medium when subjected to the heat of an arc and movable with said contact means into said bore, a trailer stud secured to said contact means and extending endwise therefrom into one end of said trailer and into the hollow portion thereof and secured thereto, and a plurality of contact fingers engaging the periphery of said contact means at said one end of said bore.

22. A circuit interrupter for opening a high voltage circuit isolating device such as a disconnecting fuse, disconnecting switch or the like, normally carrying line current and having a normally energized terminal contact member and a current carrying member movable into and out of engagement therewith comprising, in combination, a tubular insulating housing having a conducting member secured thereto carrying externally extending contact makin means for electrical connection to said contact member, an inner insulating sleeve relatively slidably mounted within said housing having a conducting member secured thereto carrying externally extending contact making means for electrical connection to said current carrying member, a pair of separable contacts in said sleeve connected respectively to said conducting members, an arc extinguishing sleeve into which one of said contacts is drawn away from the other contact to open the circuit therethrough, an arc extinguishing trailer movable into said are extinguishing sleeve to confine and extinguish therebetween the ar formed on separation of said contacts, insulating means interconnecting said one contact and said trailer, and means for separating said contacts.

23. A live line handling tool for mounting on a live line stick comprising, in combination, a strut adapted to be rigidly mounted on said stick, a prong carried by said strut and extending transversely thereof for entering a ring member of an energized electrical device to shift it from one position to another, a keeper rockably mounted on said strut in spaced relation to said prong and cooperating therewith to prevent its disengagement from said ring, said keeper being yieldable in a direction transverse to its axis of rotation to permit disconnection of said prong from said ring member by twisting said strut about the longitudinal axis of said stick, and spring biased contact means carried by said strut for maintaining contact engagement with said ring member as long as said prong is therein.

24. A live line handling tool for mounting on a live line stick comprising, in combination, a strut adapted to be rigidly mounted on said stick, a prong carried by said strut and extending transversely thereof for entering a ring member of an energized electrical device to shift it from one position to another, a keeper rockably mounted on said strut in spaced relation to said prong and cooperating therewith to prevent its disengagement from said ring, said keeper being yieldable in a direction transverse to its axis of rotation to permit disconnection of said prong from said ring member by twisting said strut about the longitudinal axis of said stick, and a resilient contact finger carried by said strut for maintaining contact engagement with said ring member as long as said prong is therein.

25. A live line handling tool for mounting on a live line stick comprising, in combination, a strut adapted to be rigidly mounted on said stick, a prong carried by said strut and extending transversely thereof for entering a ring member of an energized electrical device to shift it from one position to another, a keeper rockably mounted on said strut in spaced relation to said prong and cooperating therewith to prevent its disengagement from said ring, and a resilient contact finger carried by said strut in alignment with said prong and said keeper for maintaining contact engagement with said ring member as long as said prong is therein.

26. The invention as set forth in claim 7 wherein the latch means includes a latch of insulating material capable of withstanding mechanical shock.

27. The invention as set forth in claim 26 wherein the latch is rockably mounted on the conducting member and is biased to engage the housing for holding it in separated relation relative to the sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 1,393,344 Conrad Oct. 11, 1921 1,410,888 Carlson Mar. 28, 1922 1,752,575 Roselle Apr. 1, 1930 1,852,629 Sturges Apr. 5, 1932 2,233,826 Allison Mar. 4, 1941 2,249,662 Matthews July 15, 1941 2,272,717 Ludwig et al Feb. 10, 1942 2,434,315 Froland Jan. 13, 1948 2,599,187 Lindell et a1. June 3, 1952 2,662,139 Lindell et a1. Dec. 8, 1953 2,671,142 Lindell Mar. 2, 1954 2,671,145 Lindell Mar. 2, 1954 2,709,736 Schneider May 31, 1955 

